Mining machine rotary boring head having radially adjustable cutting arms



J M. G. THASSY MINING MACHINE ROTARY BORING HEAD HAVING r RADIALLY ADJUSTABLE CUTTING ARMS Filed Nov; 15. 1956 '3 Sheets-Sheet 1 INVENTOR By Michae1 G; Thassy 4 ATTORNEY July 1957 M. G. THASSY 2,798,708

MINING MACHINE ROTARY BORING HEAD HAVING RADIALLY ADJUSTABLE CUTTING ARMS Filed Nov. 13, 1956' '3 Sheets-Sheet 2 Fig. 2'

INVENTOR.

Michael G. Thassy BY .4 TTOPNEY M. G. THASSY MINING MACHINE ROTARY BORING HEAD HAVING July 9, 1957 RADIALLY ADJUSTABLE CUTTING ARMS v 3 Sheets-Sheet 3 Filed Nov. 13, 1956 mmvrbx. v Michael =Tha ssy Arronm'y United StatesPatent O I MINING MACHINE ROTARY BORING HEAD HAV- 9 Claims. (Cl. 262-7) This invention relates to improvements in boring heads for mining machines of the type in which at least one boring head is rotatable on a horizontal axis in advance of the machine, each boring head consisting of a rotatable hub having a radially extending arm on which is mounted forwardly projecting cutting supports. Boring heads of this general character usually include means for collapsing or retracting the outer end of the arm to facilitate withdrawal of the head from the bore, and also for clearance. while transporting or tramming the mining machine from place to place in the mine.

More particularly, the present invention relates to an improvement in the type of telescopic adjustment for the outer end of the arm such as shown in pending Anderson and Hlinsky application Serial No. 557,268, filed January 4, 1956, now Patent No. 2,772,870, on a rotary boring head whereby the adjustment may also permit the boring head to cut bores of different diameters. The present invention makes use of a pair of shiftable gears by means of which the rotation of the boring head can retract or extend the telescopic portion of the cutter arm.

The principal object of the present invention is to provide a simple and efficient boring head structure, hav ing telescopic end portions at the outer ends of the arms.

Another object of the invention is to provide a simple form and arrangement of means for adjusting the telescopic end portion of the arm relative to the hub.

The invention may best be understood by reference to the accompanying drawings, in which:

Figure 1 is a sectional elevation view of a boring head constructed in accordance with the invention;

Figure 2 is a sectional elevation view to an enlarged scale of the hub and telescopic arm; and

Figure 3 is a sectional elevation view to an enlarged scale of the actuating mechanism shown in the left end of Figure 1.

Referring now to details of the embodiment of the invention shown in the drawings, 18 indicates a boring head mounted for rotation in bearings 11 and 12 and driven by gear 13. The bearings 11 and 12 are mounted in the gear case 14 which is a portion of an auxiliary frame forming part of a mining machine. Trimming chain guides 16 and 17 are telescopically mounted on the auxiliary frame and form part of the usual equipment found on mining machines. The boring head 14 has a hub 20 at its outer end on which is mounted a center drill 19 which has a Wedging surface 21, bit holders 22 and cutter bits 23. A radial arm 24 extends from the hub 20 and has a telescopically extensible arm 26 mounted therein. The radial arm 24 may have a forwardly projecting cutter support 27 fixed thereon, with a wedging surface 28 and bit holders 22 and bits 23. The telescopic arm 26 has-a forwardly extending cutter support 29 mount.- ed on its outer extremity with bit holders 22 and bits 23 mounted thereon. A control rod 31 extends along the axis of rotation of the boring head 10 through axial bore 32.

Referring now to Figure 2, the radial arm 24 and telescopic arm 26 with their associated parts are shown in greater detail. The axial bore 32 for control rod 31 opens into a counterbore 33 of slightly larger diameter which in turn opens into a cavity 34 centrally disposed in the hub 20 of the boring head. The hub has an axial bore 36 at its front, into which is socketed the center drill 19. The center drill 19 has an axial bore 37 inalignment withbore 33. A radial bore 38 in the hub is covered by cap 39. A bore 41 and counterbore 42 extend radially from the central cavity 34 along the axis of the telescopic arm 26 and communicates with the enlarged bore 43 along the radial arm 24. The bore 43 has a key slot 44 along one side thereof. A key 46 seated in telescopic arm 26 cooperates with the keyway 44 to provide for non-rotative, but axially sliding movement of the telescopic arm 26 relative to the radial arm 24 of the boring head. The radial arm 24 has a sealing gasket 47 and a coverplate 48, at its outer end surrounding the telescopic arm 26.; i

The telescopic arm 26 has an axial bore 49 sealed at its outer end by plug 51. The inner end of the bore terminates in a shoulder 52 and a threaded bore 53. The threaded bore 53 terminates in a counter" bore 56 having a shoulder 54. An extension screw having threads 58 engages the threaded bore 53. The end of said screw is secured in the bore 49 by a nut 72 and a concave washer 73, commonly called a coned spring. A second coned spring 57 in the opposite counter bore 56 is mounted to slip freely over the threads 58 of the screw and may from time to time act as a resilient spacer between shoulder 54 of the telescopic arm and a shoulder 59 at the opposite end of the screw. Opposite shoulder 62 on screw 58 bears against the pad 61 in the hub of boring head 10. An annular portion 63 of the screw is rotatably fitted in bore 41 of head 10. A flat thrust washer 66 is held against an inner shoulder 64 of annular portion 63 by a bevel gear 68 fixed to a reduced end portion 67 of the screw as by key 69 and nut '71.

A small lateral bore 74 in hub 10 contains a fiber pellet 76 engaging annular portion 63 of'the screw and acts as a brake to prevent random rotation of the screw under vibrating condition. The fiber pellet 76 is held under tension by resilient means such as a pair of coned springs 77 and a spaced rod 78. Pressure ca the fiber pellet is adjusted by a set screw 79 threaded in the outer end of the bore 74 and accessible from the front face of the hub when the center drill 19 is removed from the latter.

The axial control rod 31 has a shoulder 81 and a reduced extension 82. The extension 82 has opposed bevel gears 84 and 87 fixed at opposite ends thereof as by a continuous keyslot 89 into which is fitted keys 83 and 88 for the respective bevel gears 84 and 87. Bevel gear 84 abuts against the shoulder 81 and is spaced from bevel gear 87 by a sleeve 86. Bevel gear 87 is secured on the outer end of extension 82 by a flat washer 96 and nut 97.

The sleeve 86 has three annular grooves 91, 92 and 93 spaced axially thereof arranged to be engaged by a ball 94 located in the extreme end of the extension screw 58. The ball is held in yieldable engagement with the sleeve by a spring (not shown) recessed as usual in the end of said extension screw. The groove 92 when engaged by the ball 94 locates the bevel gears 84 and 87 in an iuter= mediate or neutral position wherein neither gear is in engagement with the bevel gear 68 on screw 58. When the groove 93 is engaged by ball 94, gear 87 meshes with gear 68, and when groove 91 is engaged by ball 94, gear 84 meshes with gear 68. It is thus apparent that if rod 31and boring head 10 are rotated relative to each other, the extension screw 58 can be rotated either clockwise I 3 or counter-clockwise by the selective engagement of gears 84 and 87, so as to either extend or retract the telescopic arm 26 relative to the hub 10.

Figure 3 shows in detail means for securing the control rod 31 against rotation while the boring head is rotated about it and also means for shifting said control rod axially for selectively engaging or disengaging the gears 84 and 87. The rod 31 extends rearwardly through a bushing 107 at the rear end of the hub 10, and into a fluid pressure cylinder having a body 98 and end caps 102 and 103. The rod 31 is slidably fitted in bore 106 of end cap 102 and a fluid tight sealing ring 104 prevents leakage along the rod. The rod 31 has a shoulder 108 and a reduced extension 109 into which is fitted a key 112. Keyway 111 in piston 113 cooperates with key 112 for mounting a piston 113 on shaft extension 109. The piston 113 is axially abutted against the shoulder 108 of shaft 31 and is secured against axial movement relative to said shaft by a sleeve 114 abutting a flat washer 117 secured by nut 118 at the outer end of extension 109. A seal ring 119 seals the juncture of rod 31 and sleeve 114 against fluid leakage.

The back wall of the gear case 14 has a bore 126 through which the sleeve 114 extends. A counter bore 127 associated with the bore 126 has socketed therein an end cap 103 of the pressure fluid cylinder. The counter bore 127 together with bolt 128 and nut 129 both locate and secure the cylinder against axial and radial movement.

A pointer 116 is secured to the projecting end of rod 31 between the sleeve 114 and washer 117 and serves to indicate the axial position of rod 31, and whether the rod is stationary or rotating. A pointer housing 121 suitably fixed to the back wall of gear case 14 serves to protect the pointer and has parallel annular grooves 122, 123 and 124 on its inner face to serve as reference points to indicate the axial position of the rod 31.

A fluid conduit 101 is connected to a source of pressure fluid (not shown) and to body member 98 of the cylinder at bore 129. The latter bore is in alignment with a port 131 in end cap 102 which communicates with a cavity 132 in end cap 102. The cavity 132 contains a spring 133 which acts between end cap 102 and a piston 134 to urge piston 134 against shoulder 136. The piston 134 has a conical seat 141 which cooperates frictionally with a conical end of piston 113 to coact in the manner of a cone clutch. A port 139 communicates between the cavity 132 and the head of the piston 113. The piston 134 is axially slidable in the cylinder member 98 and on the rod 31 but is secured against rotation by key 138 coacting in key slot 137 of cylinder member 98.

The opposite end of the cylinder has a fluid conduit 99 similar to conduit 101 connected through a duct 142 in alignment with a port 143 which communicates with a cavity 146 containing a spring 144. A piston 147 similar to piston 134 is slidable in the cylinder and on the sleeve 114 and normally abuts a shoulder 149 in the cylinder under the urgence of a spring 144. A port 148 admits fluid to the conical face of piston 113 which may coact frictionally with the conical seat 151 of piston 147 in the manner of a cone clutch. The piston 147 is likewise axially slidable but secured against rotation by key 152 cooperating with key slot 153.

In operation, the rod 31 normally assumes the position illustrated in the drawings, in which the pistons 134 and 147 are located against their respective stops 136 and 149 under the urgence of springs 133 and 144. This affords very little axial movement for the piston 113 which is located centrally of the cylinder, preventing the gears 84 and 87 from engaging the gear 68. The pointer 116 remains in alignment with the central groove 123, indicating that the gears are disengaged and the rod 31 may rotate or may not rotate depending upon the frictional etfect of the bushing 107 of the rotating boring head or the end caps 102 and 103 of the stationary cylinder.

When it is desired to retract the telescopic arm 26, pressure fluid is admitted to conduit 99 where it flows through port 143 into cavity 146 from which it flows through port 148 to piston 113. Further admission of fluid drives the piston 113 into clutching engagement with piston 134 and continues to slide the now engaged pistons 113 and 134 axially against the urgence of spring 133. The rod 31 is thus now moved to the right and is secured against rotation by the key 112, piston 113, clutch face 141, piston 134, key 138 and cylinder body 98. If the pressure fluid through conduit 99 is released the spring 133 will return the assembly to its initial neutral position.

A similar but reversed action is obtained to move the rod to the left for extending the telescopic arm 26, by admitting pressure fluid through conduit 101. Since this action is similar to that already described for movement of the rod 31 in the opposite direction, it need not be further described.

When the rod 31 has been shifted to the right and locked against rotation as just described, it will be seen in Figure 2 that gear 84 will mesh with gear 68. While the rod 31 is secured against rotation, the boring head 10 will be rotating. The gear 68 rolls around stationary gear 84, rotating the extension screw 58 in a direction to draw the telescopic arm 26 radially inward toward hub 10. As the telescopic arm 26 draws near the end of its permissible travel the spring 57 will engage the shoulder'59 thereby increasing the resistance to further retraction. A further function of the spring 57 is to prevent the jamming of threads which may occur at the end of the travel if no resilient means were employed. As the resistance to further retraction increases, the gear 68 tends to rotate the gear 84 rather than rolling on it and this in turn rotates the rod 31, which causes pointer 116 in Figure 3 to rotate, giving the operator a visual indication that the limit of retraction has been reached. The operator can then release the pressure fluid and the gears will assume the neutral position as previously described.

During those times when the gearing is disengaged,

a fiber plug 76 backed up by spring 77, and rod 78 and adjusted by set screw 79 exert a frictional braking force on the journal portion 63 of the screw to prevent random rotation as a result of vibration.

Consider now that the telescopic arm 26 has been fully retracted and it is desired to extend the arm. Pressure fluid is admitted to conduit 101 (Fig. 3) and the rod is moved to the left and at the same time secured against rotation as previously described. The gear 87 now becomes meshed with gear 68 and gear 68 rolls around gear 87, rotating the extension screw 58 as it does so. The rotation of said screw is now in the direction to extend the telescopic arm 26. The extension may be stopped before the extremity is reached, to vary the diameter cut by the cutter support 29.

Where maximum extension is desired, the telescopic arm 26 can be extended until spring 73 engages shoulder 52, thereby increasing the turning resistance to a point where gear 68 will carry gear 87 around rather than rolling on it. As before, this rotates rod 31 and in turn rotates pointer 116 to give the operator a visual indication that the maximum limit of extension has been reached.

When the telescopic arm 26 is moved to either limit of extension or retraction, the friction clutch faces on opposite sides of the piston 113, are yieldable due to springs 133 and 144, so as to permit slippage of the clutch and protect the parts against damage.

Although I have shown and described certain embodiments of my invention, it will be understood that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In a boring machine, a frame, a rotary boring head comprising a hollow drive shaft, a hollow hub, a hollow inner arm portion extending radially from said hub and separated from said hollow hub by a transverse partition, a cutter-carrying end portion telescopically mounted in the outer end of said inner radial arm portion, an extension screw extending radially of said inner arm portion, with its outer end in threaded engagement with said telescopic outer end portion and its inner end extending through and having bearing engagement in said transverse partition, a gear fixed on the inner end of said extension screw within said hollow hub, a control shaft disposed concentrically in said hollow shaft and in rotatable and slidable relation to said shaft and hub, and a pair of opposed gears fixed on said control shaft at opposite sides of the gear on said extension screw, said gears being adapted for selective meshing engagement with the latter by slidable adjustment of said control shaft.

2. The structure of claim 1, wherein means are mounted on the frame for selectively holding the control shaft against rotation while the drive shaft is being rotated, and means are provided for shifting the control shaft longitudinally of said drive shaft to cause selective engagement with the gears on said control shaft with the gear on said extension screw.

3. The structure of claim 2, wherein the means for holding the control shaft against rotation and the means for shifting the control shaft longitudinally are disposed on the frame rearwardly of the control shaft.

4. The structure of claim 2, wherein an indicator arm is mounted on the control shaft for rotational and longitudinal movement therewith and a fixture is secured to the frame having a plurality of annular indicating marks thereon spaced axially of the control shaft in cooperative relation with the arm on said shaft to indicate the axial position of said shaft in its various positions of rotation.

5. The structure of claim 2, wherein the means for shifting the control shaft includes a cylinder fixed on the frame through which cylinder the control shaft extends, piston means non-rotatably and slidably mounted on the control shaft within said cylinder, a pair of clutch members non-rotatably and slidably mounted in the cylinder respectively adapted for selective clutching engagement with said piston'means byshifting movement of said piston means in opposite directions, means normally spacing each of the clutch members from engagement with the piston means to permit rotation of said control shaft, and hydraulic pressure inlet ports communicating with the piston means for selectively shifting the latter in opposite directions into non-rotating engagement with one of the clutch members and for simultaneously shifting the control shaft into non-rotative geared connection with the extension screw.

6. The structure of claim 5, wherein each of the hydraulic pressure inlet ducts communicating with one side of the piston means also has communication with both sides of .the adjacent clutch member.

7. The structure of claim 5, wherein the extension screw has stop means for limiting the extension and retraction of the telescopic end portion relative to the inner arm portion and the piston means and the clutch members have yieldable frictionally engageable faces to permit relative slippage between the frictionally engaged faces when the extension screw engages the stop means at the limit of extension and retraction of the telescopic end portion.

8. The structure of claim 5, wherein spring means are provided for normally urging each of the clutch members to its limit of movement toward the piston means, but permitting yieldable retractive movement of each clutch member when clutched by the piston means under hydraulic pressure effective on the opposite end of the latter.

9. The structure of claim 8, wherein the piston means consists of a single piston and the clutch members are disposed at opposite ends of said single piston.

References Cited in the file of this patent UNITED STATES PATENTS 1,953,402 Graham Apr. 3, 1934 2,772,870 Anderson et a1. Dec. 4, 1956 

